feat(automation): add Zapier and Make.com integration

Add REST hooks subscription endpoints, incoming action endpoints, and
Zapier-compatible flat payload format for automation platform integration.

- AutomationHook model for webhook subscriptions
- POST /api/automation/hooks/subscribe and DELETE /hooks/{id}
- GET /api/automation/triggers/sample/{event} for Zapier field mapping
- POST /api/automation/actions/upload for incoming document uploads
- Celery task with retry for async hook delivery
- Integration with existing webhook dispatch flow
- 30 passing tests covering all new functionality

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/utils/webhook.py

@@ -145,6 +145,8 @@ def dispatch_webhook_event(event: str, data: dict[str, Any]) -> None:
     It delegates to :func:`deliver_webhook_task` (Celery) for each matching
     webhook so delivery happens asynchronously with automatic retries.
 
+    Also dispatches to automation hooks (Zapier / Make.com) if enabled.
+
     Args:
         event: Event name (must be in :data:`VALID_EVENTS`).
         data: Event-specific payload data.
@@ -156,16 +158,23 @@ def dispatch_webhook_event(event: str, data: dict[str, Any]) -> None:
     webhooks = get_active_webhooks_for_event(event)
     if not webhooks:
         logger.debug("No active webhooks for event %s", event)
-        return
+    else:
+        payload = build_payload(event, data)
 
-    payload = build_payload(event, data)
+        # Import here to avoid circular dependency with celery_app
+        from app.tasks.webhook_tasks import deliver_webhook_task
 
-    # Import here to avoid circular dependency with celery_app
-    from app.tasks.webhook_tasks import deliver_webhook_task
+        for wh in webhooks:
+            try:
+                deliver_webhook_task.delay(wh["url"], payload, wh["secret"])
+                logger.debug("Queued webhook delivery to %s for event %s", wh["url"], event)
+            except Exception as exc:
+                logger.error("Failed to queue webhook to %s: %s", wh["url"], exc)
 
-    for wh in webhooks:
-        try:
-            deliver_webhook_task.delay(wh["url"], payload, wh["secret"])
-            logger.debug("Queued webhook delivery to %s for event %s", wh["url"], event)
-        except Exception as exc:
-            logger.error("Failed to queue webhook to %s: %s", wh["url"], exc)
+    # Also fan-out to Zapier / Make.com automation hooks
+    try:
+        from app.utils.automation_hooks import dispatch_automation_hooks
+
+        dispatch_automation_hooks(event, data)
+    except Exception as exc:
+        logger.error("Failed to dispatch automation hooks for event %s: %s", event, exc)